Im trying to install a new bb on my bike. But somehow not fitting? If i dont put the tube between the cups its ok. But somehow i feel its wrong. Any advice how to make this fit?
by kserr17
Im trying to install a new bb on my bike. But somehow not fitting? If i dont put the tube between the cups its ok. But somehow i feel its wrong. Any advice how to make this fit?
by kserr17
7 Comments
You absolutely need the tube, else that cable housing will rub on your crank spindle and cut a groove. Best case this destroys it, worst case this destroys it while causing you to crash when standing on the pedals and end up really hurt.
Figure out that cable. It likely doesn’t need that big of a loop in the frame. See if you can adjust it to fit better. And welcome to the fun of internal routing on non-carbon frames. :\
Not fitting like it doesn’t thread or it’s not even the size?
i’ve seen online someone who used the bb cable guide and drain hole to tie a zip tie that holes down the brake housing. you might be able to pull it off with the single drain hole with the correct sized zip tie. t47 should be able to fit the housing. it’s possible the bb you bought wasn’t designed with internal routing on a metal frame in mind. the Ti frame I purchased has a normal BSA inside a T47 shell. It was machined in a way that is bsa on the outside but t47 in the middle. I’m dealing with a similar issue, but will get around to it when I finish the other stuff. but yea you definitely need the sleeve. worst case scenario, you can 3d print your own sleeve that’s a bit thinner. I can help you with that as a last resort.
You 100% need to put the tube with a cable/hose there. Otherwise your spindle will gradually wear and if left long enough slice it.
Shove it back to the downtube or wherever it came from so that it doesn’t have such a big loop and pass through at only a slight bend.
I think you may need a solution like in the photograph. But there are also bottom brackets which have smaller diameter tubes for this exact reason. In your case it looks like the tube is a lot larger diameter than the axle.
https://preview.redd.it/q5xg4qzqar3e1.png?width=960&format=png&auto=webp&s=c5f1d654665a0b3f222d047c4f247393c758d822
This is a good reason to have several BB available to attempt the best fit. I have had this issue and the only way it worked for me was to use a different BB with a smaller diameter tube. I have even 3d printed tubes before, because they don’t really do much more than help prevent water ingress and internal rubbing.
https://preview.redd.it/j99auahmfr3e1.jpeg?width=1179&format=pjpg&auto=webp&s=d737d454313c25d7dbb2e2987bf925b779c4de74
May want to install new housing at this point now as well. That cut looks like it’s ready to blow out.